Tharisa Plc, the platinum and chrome miner run by the Pouroulis family, is considering investing in a $4.2 billion platinum project in Zimbabwe being developed by another company founded by the family. Tharisa would join Karo Resources, founded by mining entrepreneur Loucas Pouroulis, in building the mine, located on the Great Dyke, a 550-kilometer (342 miles) range of hills rich in metals and minerals. The investment, initially estimated at $4.2 billion, could be lower and the spending spread over eight years, according to Phoevos Pouroulis, chief executive officer of Tharisa and Loucas’s son.